Sorry for the long winded answer Peter but you did ask and offer a dither option. After much head scratching my brain feels like it's full of popping candy with names jumping in and out of the ether. If you had asked that question when I first started on my lifelong soul journey it would have been a lot easier to answer, no thought would have been needed, Otis Redding, Gladys Knight and for the group The Temptations with a nod to Sam and Dave (artist,artists not quite a group )
Time moves on and though I still love all the aforementioned such is the diversity of my taste across the spectrum of soul music I've given it some thought and can't come up with a favourite. Using the number of records in my collection by a particular artist wouldn't make them a favourite. I've probably got more records by the Supremes than anyone else but they wouldn't come close to the top. Some great choices already mentioned, both Womack and Taylor would be there about's, could I choose between two Betty's(e) , Lavette and Everett, could Kool and the Gang triumph over the Ohio Players, Marvin,Curtis, Johnny Nash, Joe Simon, whose music could I not bear to never hear again.......Peter you're a bad man , don't even think of revisiting a fav record thread .
First record I heard by Otis, Shake, hooked after that, first became aware of Womack with the Valentinos but it was Harry Hippie /I Can Understand It that had me buying all his 70's early eighties albums, Gladys would be Just Walk in My Shoes church hall disco, only artist I've got close enough to to ask for an autograph shaking like a leaf (me not Gladys).
Cheers Peter thinking about this brought back some happy memories if no specific answer.